I have a Mikuni 38 mm carb on a Chaparral GB50. It everything works great until I open the throttle up. Then gas starts dribbling out of the overflow. I have set the floats a little low trying to fix the issue but it has not helped. This machine does have a vacuum fuel pump. Is the pressure to great for the float valve? Not sure what else to use to get the fuel from the front of the Superchief to the engine.